The subject matter disclosed herein relates to detection systems for use in imaging systems, such as X-ray based and nuclear medicine imaging systems.
Conventional imaging, for example, such as single photon emission computed tomography (SPECT) and positron emission tomography (PET) may utilize a radiopharmaceutical that is administered to a patient. In the context of PET imaging, the radiopharmaceutical typically breaks down or decays within the patient, releasing a positron that annihilates when encountering an electron and produces a pair of gamma rays moving in opposite directions in the process. In SPECT imaging, a single gamma ray is generated when the radiopharmaceutical breaks down or decays within the patient. These gamma rays interact with detectors within the respective PET or SPECT scanner, which allow the decay events to be localized, thereby providing a view of where the radiopharmaceutical is distributed throughout the patient.
In the above examples of imaging technologies, a detector is employed which converts incident radiation to useful electrical signals that can be used in image formation. Certain such detector technologies employ solid state photomultipliers, which may be useful for detecting optical signals generated in a scintillator in response to the incident radiation. One issue that may arise is that, in certain detector technologies where solid state photomultipliers are employed, the large output capacitance of the solid state photomultipliers combined with the inductance and impedance of the readout circuit can produce poor timing resolution. The larger output capacitance of the solid state photomultiplier arises from the large number of micro cells connected in parallel between the bias voltage input pin and the anode output pin of the solid state photomultiplier. To reduce the output capacitance, circuitry may be added to each microcell to isolate the capacitance of the microcell from the output of the solid state photomultiplier. However, the inventors have observed that conventional circuitry configurations typically require a high current that is drawn from a separate power supply to operate, thereby increasing the power dissipated in the solid state photomultiplier. In addition, the conventional circuitry configurations require relatively large area in the microcell making the photomultiplier inefficient.
Therefore, the inventors have provided an improved solid state photomultiplier.